Lubricating oil composition



Patented Jan. 5, 1943 UNITED STATES PATENT OFFICE LUBRICATING on. COMPOSITION Edwin J. Barth, Chicago, Ill., assignor to Sinclair Refining Company, New York, N. Y., a corporation of Maine No Drawing. Application March 8, 1941,

Serial No. 382,337

5 Claims.

or more alkyl groups are directly attached to the basic phenol ring. The addition agent is present in an amount insuflicient materially to alter the normally liquid character of the petroleum lubricating oil itself, 0.5-5.0% on the oil for example. The addition agents of; m following general structure? in which R is an alkyl chain and in which R1 represents either hydrogen or one or more alkyl groups directly attached to the basic phenol ring.

xamples-of specific addition agents which have been found-suitable for use in the lubricating oil compositions of my invention are calcium ortho-stearoyl phenolate, calcium ortho-lauroyl phenolate, calcium ortho-stearoy1-4-tertiarybutyl phenolate, and calcium ortho-caproyli-B- diamyl phenolate.

The trend of development in internal combustion engines has imposed increasing burdens upon the oils used for their lubrication, particularly with the operating temperatures and pressures. Extreme requirements in both of these respects are represented by the Diesel type of engine and supercharged aircraft engines. The useful operating life of a lubricating oil, in such services, is-determined in large measure by its thermal stability and by its physical capacity to continue functioning as a lubricant at the high temperatures and pressures encountered. One measure of thermal stability is resistance to oxi dation. Oxidation promotes either the formation of sludge or the formation of acids corrosive to bearing metals, or both. However, in another aspect the effect of thermal stability is deter mined not only by the extent of oxidation or decomposition but also by the character of the products of such decomposition or oxidation and by the extent and location, within the engine, of deposits of such products. The improved lubricating oil compositions of my invention, have, in addition to the lubricating properties of the invention have the a petroleum oils ofwhich they are compounded, a

high solvent capacity for sludge of the character.

formed by oxidation of petroleum lubricating oils, and, perhaps of even greater importance, the

. property of rendering deposits of sludge and carbon within the engine soft and friable rather than hard and coherent and of disintegrating and removing such deposits as an inci- 'dent of the normal operation of the engine. In

engines of this type the high temperature to which lubricating oil is subjected, particularly at the top of the stroke, frequently causes deposition of sludge and carbonization in the groove for and behind one or more of the piston rings. Consequent sticking of the rings rapidly deprives the piston and cylinder wall of proper lubrication inducing excessive wear and, frequently, scoring of the cylinder wall. The formation of such "carbon deposits, hard enough and coherent enough to involve sticking of the rings is materially retarded, if not avoided, by the use of the lubricating' oil compositions of my invention. In my improved lubricating oil compositions the addition agents function not only to inhibit sludge formation and to modify the character of the carbon deposits, but they also function as antioxidants effective to inhibit, at least over a substantial induction period, the rate of oxygen absorption at elevated temperatures, thus rendering such lubricating oil compositions non-corrosive, or less corrosive, to alloy bearing metals.

' The synthesis of keto-phenolates by the Fries rearrangement has been fully described in the literature; for example, Journal of Organic Chemistry, V. No. 2, 165 (1940). However, the following examples will serve to illustrate the application of this general method in the preparation of specific addition agents suitable for use in the compositions of my invention. Phenyl laurate was made from 425 grams (4.5 mols) of phenol in 800 cc. of dry carbon disulphide. To this mixture was added slowly 600 grams (4.5 mols) of aluminum chloride, and finally 656 grams (3.0 mols) of lauroyl chloride was added drop by drop while the'mixture was being rapidly stirred. Esterification was allowed to proceed overnight at the reflux temperature. Oarbon disulphide was then distilled off and the residue heated to 340 F. for 2 hours to complete the Fries re-arrangement. The reaction product was then cooled and washed in succession with concentrated hydrochloric acid and with water, then dried, and finally distilled. The distillate was saponified with sodium hydroxide in a solution containing equal parts of alcohol and water same general procedure,

lowing comparison of to destroy any phenyl esters. The ortho-lzetm phenolates were then precipitated with carbon dioxide. The calcium phenolate was prepared by dissolving 2'16 grams (1 mol) of ortho-lauroyl phenol and 44 grams (1.1 mol) of sodium hydroxide in 300 cc. of alcohol. While this solution was rapidly stirred there was added 500 cc. of benzene and finally 6'7 grams (0.6 mol) of calcium chloride in 200 cc. of water. Stirring was continued for 3 minutes, after which the benzene layer containing the calcium ortho-lauryol phenolate was separated and the benzene removed by vacuum distillation, The final product was found to have a calcium content of 6.15 as compared to a calculated calcium content of 6.8.

In a second preparation, using this same general procedure; stearic acid chloride was first condensed with para tertiary butyl phenol. The final product, calcium ortho-stearoyl-4-t-butyl phenolate, was found to have a calcium content of 5.0% as compared to a calculated calcium content of 4.6. In a third preparation, using the caproic acid chloride was first condensed with 2,4-diamyl phenol. The final product, calcium ortho-caproyl-4-6-diamyl phenolate, was found to have a calcium content of 6.88% as compared to a calculated calcium content of 7.11%.

The calcium ortho-keptophenolates of my invention generally are viscous liquids. They are highly oil soluble even in lubricating oils of high paraflinicity and high viscosity index. When incorporated in a petroleum lubricating oil base they cause a marked increase in sludgin time as indicated by the Indiana oxidation test." The extent of the increase in sludging time varies with the amount of the addition agent and is different for different base oils. The eflect on the I. S. T. of various base oils upon addition of 1.33% of calcium ortho-stearoyl phenolate is illustrated in the following table in which the base oils were derived respectively from a South Texas crude, a Mid-Continent crude and a Pennsylvaniacrude:

Base oil I S. T L S '1 Vis. at Vis. at

V. I. blank of oil blend South Texas 513.1 53.6 14.4 15.0 30.5 Mid-continent 525.9 61. o 77.9 18.0 35.0 Pennsylvania 463.0 67.8 100.3 68.0 320.0

The relative effect of several different addition agents on the sludging time of the same base oil is illustrated by comparison of the I. S. T. of the several blends included in the following table. In each of these blends the base oil used was the same Pennsylvania type petroleum stock as that used in preparation of the blend listed last in the foregoing table. Each blend contained 1.33% by weight on the oil of the addition agent. Addition agent in blend: I. S. T. Blank base-oil 68.0

Calcium ortho-stearoyl phenolate 320.0 Calcium ortho-lauroyl phenolate 370.0 Calcium ortho-stearoyl-4-tertiary butyl phenolate Calcium ortho-caproyl 4-6-diamyl phenolate above 350 The advantages of my improved lubricating composition are further illustrated by the-folthe results obtained in 22.3 cc. per minute per 100 grams of Gravity A. P. 1.... Flash F two Lawson engine tests, using as the lubricant instance and in the other a my invention compounded from the same base oil and 1.33% by weight of cal cium ortho-stearoyl phenolate. The properties of the base oil, a solvent treated petroleum lubricating oil, and of the blend used in these tests are given in the following table:

tion in the test on the blend showed that all rings were free and adequately lubricated "although the piston was very lightly lacquered.

The anti-oxidant action oi the addition agents embodied in the lubricating oil compositions of my invention varies with the particular addition agent and with the amount of the addition agent. In general an increase in the amount of the addition agent does not materially. alter the rate of oxygen absorption during the induction period but does prolong the induction period during which the rate of oxygen Accelerated oxygen absorption tests conducted at 400 F. with pure ongen will serve to illustrate the anti-oxidant action of the addition agents in the improved lubricating oil compositions of my invention. The base oil for the blends tested in these omen absorption tests was a double-- solvent-treated Pennsylvania type petroleum lubricating oil having a gravity of 28.2 A. P.'I.. a viscosity of 1445 seconds at F. and of 119.2 seconds at 210 F. Under the test conditions the rate of oxygen absorption for the blank oil was oil. The addition of 1% by weight of calcium ortho-stearoyl phenolate reduced the rate or oxygen absorption during the induction period to 8.6 cc. per minute. The induction period of this blend under the accelerate'd test conditions was 22 minutes. The addition of 2% by weight of calcium orthostearoyl-4-tertiary butyl phenolate to the same base oil reduced the rate of oxygen absorption during the induction period to 7.2 cc. per minute and increased the induction period to 49 minutes. The addition of 2% of calcium ortho-caproyl 4-8- diamyl phenolate to the same base oil reduced the rate of oxygen absorption from 223 cc. per minute to 8.2 cc. per minute during an induction period of 34 minutes.

If desired addition agents other than calcium ketophenolates and the specified derivatives thereof, the uses of which for various specific purposes, such as to increase oiliness or film strength, to depress the pour point and the like, are well known, may also be incorporated in the lubricating compositions of my invention. In general absorption is retarded.

the group consisting of calcium ortho-ketophenolates and substituted derivatives thereof in which the substituent is at least one alkyl group directly attached to the basic phenol ring.

3. A liquid lubricating oil composition comprising a petroleum lubricating oil and calcium ortho-stearoyl phenolate.

4. A liquid lubricating oil composition comprising a petroleum lubricating oil and calcium ortho-lauroyl phenolate.

5. A liquid lubricating oil composition comprising a petroleum lubricating oil and calcium ortho-caproyl 4-6-diamyl phenolate.

EDWIN J. EARTH. 

